| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [art] [num] year period of | 12 |
|
| 2 | [art] [num] year period of | 12 |
|
| 3 | a [num] year period of | 7 |
|
| 4 | a [num] year period of | 7 |
|
| 5 | the [num] year period of | 5 |
|
| 6 | the [num] year period of | 5 |
|
| 7 | [num] year period of [noun sg] | 7 |
|
| 8 | [num] year period of [noun] | 7 |
|
